Frequency distribution in intraoperative stimulation-evoked EMG responses during selective dorsal rhizotomy in children with cerebral palsy-part 1: clinical setting and neurophysiological procedure.

INTRODUCTION: Selective dorsal rhizotomy (SDR) consists of microsurgical partial deafferentation of sensory nerve roots (L1-S2). It is primarily used today in decreasing spasticity in young cerebral palsy (CP) patients. Intraoperative monitoring (IOM) is an essential part of the surgical decision-making process, aimed at improving functional results. The role played by SDR-IOM is examined, while realizing that connections between complex EMG responses to nerve-root stimulation and a patient's individual motor ability remain to be clarified. METHODS: We conducted this retrospective study, analyzing EMG responses in 146 patients evoked by dorsal-root and rootlet stimulation, applying an objective response-classification system, and investigating the prevalence and distribution of the assessed grades. Part1 describes the clinical setting and SDR procedure, reintroduced in Germany by the senior author in 2007. RESULTS: Stimulation-evoked EMG response patterns revealed significant differences along the segmental levels. More specifically, a comparison of grade 3+4 prevalence showed that higher-graded rootlets were more noticeable at lower nerve root levels (L5, S1), resulting in a typical rostro-caudal anatomical distribution. CONCLUSIONS: In view of its prophylactic potential, SDR should be carried out at an early stage in all CP patients suffering from severe spasticity. It is particularly effective when used as an integral part of a coordinated, comprehensive spasticity program in which a team of experts pool their information. The IOM findings pertaining to the anatomical grouping of grades could be of potential importance in adjusting the SDR-IOM intervention to suit the specific individual constellation, pending further validation. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03079362.

Combined vs. Isoflurane/Fentanyl anesthesia for major abdominal surgery: Effects on hormones and hemodynamics.

BACKGROUND: Combination of epidural and general anesthesia (combined anesthesia) avoids the intraoperative use of intravenous analgesics and may reduce the surgical stress response during major abdominal surgery. This study examines the differences in intraoperative hemodynamic stability, cortisol levels and activity of cardiovascular hormones between combined anesthesia and isoflurane/fentanyl anesthesia. MATERIAL/METHODS: Sixty ASA I-II patients were prospectively randomized to receive either combined anesthesia, i.e, isoflurane anesthesia combined with thoracic epidural analgesia (bolus of 12 ml 0.2% ropivacaine containing 1 microg/ml sufentanil 30 min before incision, followed by continuous infusion at 6 ml/h) or isoflurane/fentanyl anesthesia (IV fentanyl as required) for major abdominal surgery. Depth of anesthesia was monitored using Bispectral Index. Administration of fluids and of vasopressors was directed by a standardized protocol. Blood samples for angiotensin II, vasopressin, catecholamines, and cortisol were drawn before anesthesia, after induction (but before using the epidural catheter), and 40 min after skin incision. RESULTS: After induction of anesthesia, mean arterial pressure decreased by 12-20 mmHg in both groups and angiotensin-II concentrations increased. Vasopressin increased predominantly after opening the abdomen in both groups. Under combined anesthesia, intraoperative epinephrine and cortisol concentrations were considerably lower. Intraoperative crystalloid fluid substitution, blood loss and urine output did not differ between groups. There were more hypotensive periods and the demand for colloids and low-dose continuous norepinephrine was greater under combined anesthesia. CONCLUSIONS: Combined anesthesia reduces the intraoperative stress response, but moderate hemodynamic instability is relatively common and has to be compensated for by adequate volume replacement and vasopressor support.